The invention relates to friction supporting stays, for windows, of the kind comprising a track, a slider movable along the track, a strut pivotally connected to the track, a brace pivotally connected between the slider and the strut, a link pivotally connected to the slider, and a bar pivotally connected to the link and to the strut, the arrangement being such that as the slide moves along the track the bar can swing from a position overlying the track to a position where it is angled with respect to the track.
In use, two such supporting stays are normally provided at opposite sides of a window, the track of each stay being mounted on the window frame and the bar being mounted on the window sash. The arrangement is such that as the window pivots on the stays, about either a vertical or a horizontal axis, the axis of pivoting of the window sash moves away from the window frame so that when the window is open both sides thereof are accessible from one side of the window frame.
The window sash is frictionally restrained in any angular position to which it is set. This frictional restraint may be provided partly by the friction at the pivotal connections between the various elements but is largely provided by the frictional engagement between the slider and the track.
In friction supporting stays of this kind, the end of the track remote from the strut is normally provided with a cap member providing two internal cam surfaces meeting at an apex, and the end of the bar which overlies the track when the stay is in the closed position is provided with a correspondingly shaped nose portion which enters the cap member and engages the cam surfaces with a wedging action as the stay is moved into the closed position.
Normally, the shape of the cap member and the shape of the nose portion are symmetrical so that the stay may be opened in either direction from the closed position. However, in stays above a certain size, for use with large windows, there is inevitably some deflection of the components of the stay due to the weight of the window and it is sometimes found that, due to this deflection, the nose portion on the bar becomes displaced from its designed path of movement as the window is closed so that it does not enter the cap member and engage the cam surfaces but instead strikes the outer surface of the cap member. The present invention provides a modified shape of cap member and nose portion in such a stay to overcome this problem and thus render the stay suitable for use in large sizes and with heavy windows.